Added docs about building Plotly correctly with Angular

[marcj]

Added correct howto to build plotly + angular. Removed old variants since ng eject is not possible anymore and not building with webGl is basically useless..

[etpinard]

Thanks very much for the PR!

I've never used plotly.js with angular, so I'll ping @andrefarzat and @TomDemulierChevret who could maybe helps us review your patch.

[TomDemulierChevret]

I don't have time to test this right now, but it seems pretty alright.

The only issue for me is that it should include an example with a partial bundle (and if possible a custom bundle) like the existing documentation.

[marcj]

What is a "partial bundle" and where is the custom bundle?

[TomDemulierChevret]

https://github.com/plotly/plotly.js/blob/master/dist/README.md#partial-bundles
https://github.com/plotly/plotly.js#modules

You don't want to bundle the whole plotly.js lib in your app if you only use a specific subset of charts.

The current version of the doc didn't cover custom bundle, but it had an exemple for partial bundle (in the "src/tsconfig.app.json" part).

[thatsmeta]

I found this PR very helpful when trying to build plotly with Angular.
As far as I understand, you can create a custom bundle in about the same way as described here: https://github.com/plotly/plotly.js#modules.

import Plotly from 'plotly.js/lib/core';
import scatter from 'plotly.js/lib/scatter';
import scattergl from 'plotly.js/lib/scattergl';

Plotly.register([
    scatter,
    scattergl
]);

export { Plotly };

[alexcjohnson]

As long as Angular users have found this helpful, that's good enough for me! 💃